const-correctness fixes for regex

[Jim Meyering]

A week or so ago, I stumbled across one interface that was missing a
`const' attribute on a parameter, then dug up a few more.  Paul, let me
know when you reach a point at which my checking this in won't interfere.


Index: regcomp.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/regcomp.c,v
retrieving revision 1.9
diff -u -p -r1.9 regcomp.c
--- regcomp.c   25 Aug 2005 20:39:57 -0000      1.9
+++ regcomp.c   31 Aug 2005 20:43:01 -0000
@@ -45,8 +45,9 @@ static bin_tree_t *lower_subexp (reg_err
 static reg_errcode_t calc_first (void *extra, bin_tree_t *node);
 static reg_errcode_t calc_next (void *extra, bin_tree_t *node);
 static reg_errcode_t link_nfa_nodes (void *extra, bin_tree_t *node);
-static int duplicate_node (re_dfa_t *dfa, int org_idx, unsigned int 
constraint);
-static int search_duplicated_node (re_dfa_t *dfa, int org_node,
+static int duplicate_node (re_dfa_t *dfa, int org_idx,
+                          unsigned int constraint);
+static int search_duplicated_node (const re_dfa_t *dfa, int org_node,
                                   unsigned int constraint);
 static reg_errcode_t calc_eclosure (re_dfa_t *dfa);
 static reg_errcode_t calc_eclosure_iter (re_node_set *new_set, re_dfa_t *dfa,
@@ -1506,7 +1507,8 @@ duplicate_node_closure (re_dfa_t *dfa, i
    satisfies the constraint CONSTRAINT.  */
 
 static int
-search_duplicated_node (re_dfa_t *dfa, int org_node, unsigned int constraint)
+search_duplicated_node (const re_dfa_t *dfa, int org_node,
+                       unsigned int constraint)
 {
   int idx;
   for (idx = dfa->nodes_len - 1; dfa->nodes[idx].duplicated && idx > 0; --idx)
Index: regex_internal.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/regex_internal.c,v
retrieving revision 1.9
diff -u -p -r1.9 regex_internal.c
--- regex_internal.c    26 Aug 2005 21:47:52 -0000      1.9
+++ regex_internal.c    31 Aug 2005 20:43:01 -0000
@@ -21,10 +21,10 @@ static void re_string_construct_common (
                                        re_string_t *pstr,
                                        REG_TRANSLATE_TYPE trans, int icase,
                                        const re_dfa_t *dfa) internal_function;
-static re_dfastate_t *create_ci_newstate (re_dfa_t *dfa,
+static re_dfastate_t *create_ci_newstate (const re_dfa_t *dfa,
                                          const re_node_set *nodes,
                                          unsigned int hash) internal_function;
-static re_dfastate_t *create_cd_newstate (re_dfa_t *dfa,
+static re_dfastate_t *create_cd_newstate (const re_dfa_t *dfa,
                                          const re_node_set *nodes,
                                          unsigned int context,
                                          unsigned int hash) internal_function;
@@ -1461,7 +1461,7 @@ re_acquire_state_context (reg_errcode_t 
 
 static reg_errcode_t
 internal_function
-register_state (re_dfa_t *dfa, re_dfastate_t *newstate, unsigned int hash)
+register_state (const re_dfa_t *dfa, re_dfastate_t *newstate, unsigned int 
hash)
 {
   struct re_state_table_entry *spot;
   reg_errcode_t err;
@@ -1498,7 +1498,7 @@ register_state (re_dfa_t *dfa, re_dfasta
 
 static re_dfastate_t *
 internal_function
-create_ci_newstate (re_dfa_t *dfa, const re_node_set *nodes, unsigned int hash)
+create_ci_newstate (const re_dfa_t *dfa, const re_node_set *nodes, unsigned 
int hash)
 {
   int i;
   reg_errcode_t err;
@@ -1547,7 +1547,7 @@ create_ci_newstate (re_dfa_t *dfa, const
 
 static re_dfastate_t *
 internal_function
-create_cd_newstate (re_dfa_t *dfa, const re_node_set *nodes,
+create_cd_newstate (const re_dfa_t *dfa, const re_node_set *nodes,
                    unsigned int context, unsigned int hash)
 {
   int i, nctx_nodes = 0;
Index: regexec.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/regexec.c,v
retrieving revision 1.9
diff -u -p -r1.9 regexec.c
--- regexec.c   26 Aug 2005 05:58:55 -0000      1.9
+++ regexec.c   31 Aug 2005 20:43:02 -0000
@@ -24,7 +24,7 @@ static void match_ctx_free (re_match_con
 static reg_errcode_t match_ctx_add_entry (re_match_context_t *cache, int node,
                                          int str_idx, int from, int to)
      internal_function;
-static int search_cur_bkref_entry (re_match_context_t *mctx, int str_idx)
+static int search_cur_bkref_entry (const re_match_context_t *mctx, int str_idx)
      internal_function;
 static reg_errcode_t match_ctx_add_subtop (re_match_context_t *mctx, int node,
                                           int str_idx) internal_function;
@@ -89,13 +89,14 @@ static reg_errcode_t update_cur_sifted_s
 static reg_errcode_t add_epsilon_src_nodes (re_dfa_t *dfa,
                                            re_node_set *dest_nodes,
                                            const re_node_set *candidates) 
internal_function;
-static int check_dst_limits (re_match_context_t *mctx, re_node_set *limits,
+static int check_dst_limits (const re_match_context_t *mctx,
+                            const re_node_set *limits,
                             int dst_node, int dst_idx, int src_node,
                             int src_idx) internal_function;
-static int check_dst_limits_calc_pos_1 (re_match_context_t *mctx,
+static int check_dst_limits_calc_pos_1 (const re_match_context_t *mctx,
                                        int boundaries, int subexp_idx,
                                        int from_node, int bkref_idx) 
internal_function;
-static int check_dst_limits_calc_pos (re_match_context_t *mctx,
+static int check_dst_limits_calc_pos (const re_match_context_t *mctx,
                                      int limit, int subexp_idx,
                                      int node, int str_idx,
                                      int bkref_idx) internal_function;
@@ -168,7 +169,7 @@ static unsigned int find_collation_seque
                                                   size_t name_len) 
internal_function;
 # endif /* _LIBC */
 #endif /* RE_ENABLE_I18N */
-static int group_nodes_into_DFAstates (re_dfa_t *dfa,
+static int group_nodes_into_DFAstates (const re_dfa_t *dfa,
                                       const re_dfastate_t *state,
                                       re_node_set *states_node,
                                       bitset *states_ch) internal_function;
@@ -1834,7 +1835,7 @@ sub_epsilon_src_nodes (re_dfa_t *dfa, in
 
 static int
 internal_function
-check_dst_limits (re_match_context_t *mctx, re_node_set *limits,
+check_dst_limits (const re_match_context_t *mctx, const re_node_set *limits,
                  int dst_node, int dst_idx, int src_node, int src_idx)
 {
   re_dfa_t *const dfa = mctx->dfa;
@@ -1870,7 +1871,7 @@ check_dst_limits (re_match_context_t *mc
 
 static int
 internal_function
-check_dst_limits_calc_pos_1 (re_match_context_t *mctx, int boundaries,
+check_dst_limits_calc_pos_1 (const re_match_context_t *mctx, int boundaries,
                             int subexp_idx, int from_node, int bkref_idx)
 {
   re_dfa_t *const dfa = mctx->dfa;
@@ -1948,7 +1949,8 @@ check_dst_limits_calc_pos_1 (re_match_co
 
 static int
 internal_function
-check_dst_limits_calc_pos (re_match_context_t *mctx, int limit, int subexp_idx,
+check_dst_limits_calc_pos (const re_match_context_t *mctx,
+                          int limit, int subexp_idx,
                           int from_node, int str_idx, int bkref_idx)
 {
   struct re_backref_cache_entry *lim = mctx->bkref_ents + limit;
@@ -3458,7 +3460,7 @@ out_free:
 
 static int
 internal_function
-group_nodes_into_DFAstates (re_dfa_t *dfa, const re_dfastate_t *state,
+group_nodes_into_DFAstates (const re_dfa_t *dfa, const re_dfastate_t *state,
                            re_node_set *dests_node, bitset *dests_ch)
 {
   reg_errcode_t err;
@@ -4179,7 +4181,7 @@ match_ctx_add_entry (re_match_context_t 
 
 static int
 internal_function
-search_cur_bkref_entry (re_match_context_t *mctx, int str_idx)
+search_cur_bkref_entry (const re_match_context_t *mctx, int str_idx)
 {
   int left, right, mid, last;
   last = right = mctx->nbkref_ents;